#include <iostream>
#include <cstdlib>
#include <unistd.h>


bool GetQueryString(std::string &query_string)
{
    bool result = false;
    std::string method = getenv("METHOD");
    if(method == "GET"){
        query_string = getenv("QUERY_STRING");
        result = true;
    }
    else if(method == "POST"){
        int content_length = atoi(getenv("CONTENT_LENGTH"));
        char c = 0;
        while(content_length){
            read(0,&c,1);
            query_string.push_back(c);
            content_length--;
        }
        result = true;
    }
    else{
        result = false;
    }
    return result;
}

void CutString(std::string &in, const std::string &sep, std::string &out1, std::string &out2)
{
    auto pos = in.find(sep);
    if(std::string::npos != pos){
        out1 = in.substr(0,pos);
        out2 = in.substr(pos+sep.size());
    }
}

int main()
{
    std::string query_string;
    GetQueryString(query_string);
    // a=100&b=200

    std::string str1;
    std::string str2;
    CutString(query_string,"&",str1,str2);

    std::string name1;
    std::string value1;
    CutString(str1,"=",name1,value1);

    std::string name2;
    std::string value2;
    CutString(str2,"=",name2,value2);

    std::cout << name1 << " : " << value1 << std::endl;
    std::cout << name2 << " : " << value2 << std::endl;

    std::cerr << name1 << " : " << value1 << std::endl;
    std::cerr << name2 << " : " << value2 << std::endl;
    int x = atoi(value1.c_str());
    int y = atoi(value2.c_str());

    //可能向进行某种计算(计算，搜索，登陆等)，想进行某种存储(注册)
    std::cout << "<html>";
    std::cout << "<head><meta charset=\"utf-8\"></head>";
    std::cout << "<body>";
    std::cout << "<h3> " << value1 << " + " << value2 << " = "<< x+y << "</h3>";
    std::cout << "<h3> " << value1 << " - " << value2 << " = "<< x-y << "</h3>";
    std::cout << "<h3> " << value1 << " * " << value2 << " = "<< x*y << "</h3>";
    std::cout << "<h3> " << value1 << " / " << value2 << " = "<< x/y << "</h3>";
    std::cout << "</body>";
    std::cout << "</html>";

    return 0;
}